Bathochromic shift

It can occur because of a change in environmental conditions: for example, a change in solvent polarity will result in solvatochromism.[2]

A series of structurally-related molecules in a substitution series can also show a bathochromic shift. Bathochromic shift is a phenomenon seen in molecular spectra, not atomic spectra; it is thus more common to speak of the movement of the peaks in the spectrum rather than lines.

${\displaystyle \Delta \lambda =\lambda _{\mathrm {observed} }^{\mathrm {state2} }-\lambda _{\mathrm {observed} }^{\mathrm {state1} }}$ where ${\displaystyle \lambda }$ is the wavelength of the spectral peak of interest and ${\displaystyle \lambda _{\mathrm {observed} }^{\mathrm {state2} }>\lambda _{\mathrm {observed} }^{\mathrm {state1} }}$

Bathochromic shift is typically demonstrated using a spectrophotometer, colorimeter, or spectroradiometer.

• Chromism
• Solvatochromism
• Spectroscopy